The present invention relates to an improved lifting anchor for embedment in concrete member, such as a precast or tilt-up wall. In its more specific aspects, the invention is directed to such an anchor which comprises an elongate bar having divergent surfaces which face outwardly to direct axial pull-out forces imparted to the bar divergently and laterally into a concrete member within which the anchor is embedded. The invention is also concerned with such an anchor wherein divergent wings extend laterally from the bar to direct lateral forces imparted to the anchor in divergent directions relative to the bar.
The prior art relative to the present invention is typified by U.S. Pat. Nos. 3,883,170 and 4,173,856. These patents each relate to lifting anchors for embedment in concrete members and a quick release hoisting shackle or coupling engageable with these anchors. The anchors in the '170 patent take the form of bars having split divergent ends or ends turned upon themselves to resist pull-out. The anchors of the '856 patent also employ bars having split divergent ends to resist pull-out. The later patent is especially directed to an improved construction for the top of the anchor to avoid spalling or break-out of the surface of the concrete member by a coupling engaged with the member.
U.S. Pat. Nos. 4,367,892; 4,580,378 and 4,930,269 are also of interest in that they disclose anchors for use with lifting shackles or couplings of the type with which the anchor of the present invention is intended to be used. The anchors of the '892 patent are of a T-shaped configuration to resist pull-out and are generally formed by casting. The anchors of the '378 patent are stamped and embody a pin which extends transversely through the anchor to resist pull-out. The anchors of the '269 patent are formed of heavy wire stock which is bent into an inverted V-shaped configuration and has integrally formed laterally extending distal ends which are formed by bending and provide resistance to pull-out.
The anchor of the present invention is fabricated of flat steel stock corresponding generally to that of the anchors in the '170 and '856 patents and is adapted to be engaged by a lifting coupling or shackle of the type shown in these patents.